View Full Version : How to:EM1/Primal Stock LPR mod(Get the most out of your stock EM1 LPR)

10-18-2008, 06:25 PM
So I been doing a couple "how to's/tutorials" (whatever you wanna call them) on the EM1 lately and i figured I would add another to the list(even though no one around here has one anymore:D ). Again I am not good at writing,spelling, explaining or describing things so try your best to understand:p ! I will be held fully responsible for any damage to your gun if you screw up (NOT) This is what we are working with here. A stock EM1 or Primal LPR. I am using an EM1 LPR in this case but a Primal one will work even better since it is already a better LPR than the EM1's.
Here is a little mod I used to do awhile back. It basically modifys your stock LPR for much much more flow and much more consistancy! I believe bushy guys do this alot too. So if you can't afford that cocker LPR mod yet than this is the thing to do and its almost as good! First thing is first though .....disassemble that LPR!
Now looking at the port on the LPR where the pressure comes out you will see that its pretty small compared to the large slit in the body. This really restricts the flow! So I not only drill that bizatch out bigger I add more holes! I used used about a 5/64 drill bit to drill 3 extra holes around the LPR along with widening the original hole. (thats four holes in all) The holes have to be drilled at about a 45* angle like the original one. I recomend doing this will a drill press!
Next, you can drill out the center hole a bit larger to increase flow. This is the hole in the center of the LPR looking from the back of it. Unfortunately I forgot to take a picture of it! I used a 5/32 drill bit to do it .

After that its time to polish all the moving parts. First i started with the piston. First take your O-ring off . Then the way i did it is I put the piston stem in a drill and spun it. Then using heavier grit sandpaper I kinda smoothed it down and reshaped the edges a bit. Then I used lighter grit sandpaper to polish it up and make it super smooth!
Before: http://i65.photobucket.com/albums/h207/BassThrasher27/LPR%20mod/IMG_1090.jpg

Then I polished and reshaped the brass cup a little bit using the same process. Unfortunately I forgot to take a picture of that but I don't think you need one .

Next I used light grit sandpaper to smooth and polish the inside of the LPR body where all the moving parts are. This just helps everything move around more smoothly.

Final step I deburred the holes and removed all the shavings. This is very very important because you don't want any shavings getting in your solenoid!! When your done with that fully reassemble your LPR and oil up. Now put it on your gun , adjust it to your desired PSI and test the fugger out! You will notice a difference in consistancy I promise!!
(Add ya a bushmaster LPR adjustable knob cap like the Planet Eclipse knob and you'll will really have a nice LPR haha )